Multiple gear stage automatic transmission

ABSTRACT

A multiple stage transmission of a planetary design having first, second and third planetary gear sets (P 1 , P 2 , P 3 ), at least first, second, third, fourth, fifth sixth rotatable shafts ( 1, 2, 3, 4, 5, 6 ), first and second brakes ( 03, 04 )and first, second, third and fourth clutches ( 14, 15, 36, 56 ). Selective engagement of the planetary gear sets (P 1 , P 2 , P 3 ), the rotatable shafts ( 1, 2, 3, 4, 5, 6, ), the brakes ( 03, 04 ) and the clutches ( 14, 15, 36, 56 ) produces different reduction ratios between the drive shaft and the driven shaft such that at least seven forward gears and at least one reverse gear are achieved.

This application claims priority from German Application Ser. No. 103 40732.4 filed Sep. 4, 2003.

FIELD OF THE INVENTION

The invention concerns a multiple stage transmission, particularly anautomatic transmission for a motor vehicle.

BACKGROUND OF THE INVENTION

In the prior art, automatic transmission, particularly for motorvehicles, comprise planetary gear sets shifted by means of friction andshifting elements such as clutches and brakes and usually have onestarting element, such as a hydrodynamic converter or a fluid clutch,optionally provided with a lock-up clutch and subject to a slip effect.

Such a transmission results from EP 0 434 525 A1. It essentiallycomprises one drive shaft and one driven shaft disposed parallel witheach other, one double planetary gear set disposed concentrically withthe driven shaft and five shifting elements in the form of threeclutches and two brakes, the optional locking of which by pairsdetermines the different gear ratios between the drive shaft and thedriven shaft. This transmission has a front-mounted range change set andtwo power paths so that six forward gears are obtained by selectiveengagement by pairs of the five shifting elements.

Here two clutches are needed in the first power path for transmittingthe torque from the front-mounted range change set to two elements ofthe double planetary gear set. These are situated in the power flowdirection essential downstream of the front-mounted range change set inthe direction of the double planetary gear set. In the second powerpath, one other clutch is provided which loosely connects it withanother element of the double planetary gear set. The clutches arearranged here so that the internal disc carrier constitutes the output.

In addition, the U.S. Pat. No. 6,139,463 publication has disclosed acompact multiple stage transmission of a planetary design, particularlyfor motor vehicles, which has two planetary gear sets and onefront-mounted range change set, the same as three clutches and twobrakes. In this known multiple stage transmission, two clutches C-1 andC-3 are provided in a first power path for transmitting the torque fromthe front-mounted range change set to the two planetary gear sets. Theexternal disc carrier or the cylinder or piston and pressurecompensation side of the clutch C-3 is here connected with a first brakeB1. Besides, the internal disc carrier of the third clutch C-3 isconnected with the cylinder or piston and pressure compensation side ofthe first clutch C-1, the internal disc carrier of the first clutch C-1is located on the output side and connected with a sun gear of the thirdplanetary gear set.

From the Applicant's DE 199 49 507 A1 is further known a multiple stagetransmission where two non-shiftable front-mounted range change sets areprovided on the drive shaft which, on the output side, produce tworotational speeds which, together with the rotational speed of the driveshaft, are optionally shiftable by selective engaging of the usedshifting elements, to a shiftable double planetary gear set acting uponthe driven shaft in a manner such that to change over from one gear tothe next sequential higher or lower gear of the two specificallyactuated shifting elements, respectively, only one shifting element hasto be engaged or disengaged.

From DE 199 12 480 A1 is known an automatically shiftable motor vehicletransmission having three spider planetary gear sets, the same as threebrakes and two clutches, for shifting six forward gears and one reversegear and having one drive shaft and one driven shaft. The automaticallyshiftable motor vehicle transmission is designed so that the drive shaftis directly connected with the sun gear of the second planetary gear setand the drive shaft is connectable, via the first clutch, with the sungear of the first planetary gear set and/or via the second clutch withthe spider of the first planetary gear set. Additionally oralternatively, the sun gear of the first planetary gear set isconnectable, via the first brake, with the housing of the transmissionand/or the spider of the first planetary gear set with the housing, viathe second brake, and/or the sun gear of the third planetary gear setwith the housing via the third brake.

DE 102 13 820 A1 has also disclosed a multiple stage automatictransmission comprising one first input path T1 of a first reductionratio; one input path T2 which has a higher reduction ratio than saidinput path T1; one planetary gear set having four elements, said fourelements being one first element, one second element, one third elementand one fourth element in the sequence of elements in a rotational speeddiagram; one clutch C-2 which transmits rotation of the input path T2 tothe first element S 3; and clutch C-1 which transmits the rotation fromthe input path T2 to the fourth element S2; one clutch C-4 whichtransmits rotation from the input path T1 to the first element; oneclutch C-3 which transmits rotation from the input path T1 to the secondelement C-3; one brake B-1 which creates engagement of the fourthelement; one brake B-2 which creates engagement of the second element;and one output element coupled with the third element R3.

With the scope of the Applicant's DE 101 15 983 A1 is described amultiple stage transmission having one drive shaft connected with afront-mounted range change set, one driven shaft connected with arear-mounted range change set and having a maximum of seven shiftingelements by the optional shifting of which at least seven forward gearscan be shifting without group shift. The front-mounted range change setis formed by a front-mounted planetary gear set or a maximum of twonon-shiftable front-mounted planetary gear sets coupled with thefront-mounted planetary gear set, the rear-mounted range change set isdesigned as a two-spider-four shaft transmission with two shiftablerear-mounted range change sets and four free shafts. The first freeshaft of said two-spider-four shaft transmission is connected with thefirst shifting element, the second free shaft with the second and thirdshifting elements, the third free shaft with the fourth and fifthshifting elements and the fourth free shaft is connected with the drivenshaft. For a multiple stage transmission with a total of six shiftingelements, the invention additionally proposes to connect the third freeshaft or the first free shaft of the rear-mounted range change set witha sixth shifting element. For a multiple stage transmission having atotal of seven shifting elements, the invention proposes connecting thethird free shaft additionally with a shift shifting element D′ and thefirst free shaft additionally with a seventh shifting element.

Within the scope of the Applicant's DE 101 15 987 has been described amultiple stage transmission having at least seven gears. Saidtransmission, together with the drive shaft and the driven shaft,comprises one non-shiftable front-mounted range change set and oneshiftable rear-mounted range change set in the form of a two-spider-fourshaft transmission. The front-mounted range change set comprises onefirst planetary gear set which, together with the input rotational speedof the drive shaft, offers a second rotational speed which canoptionally be shifted to a rear-mounted range change set. Therear-mounted range change set consists of two shiftable planetary gearsets which, with the six shifting elements, can shift at least sevengears, with two power paths being formed. At the same time, group shiftsare always advantageously prevented during each shifting operation. One9-gear multiple stage transmission has further become known from DE 2936 969; it comprises eight shifting elements and four gear sets.

Automatically shiftable vehicle transmissions of a planetary design havealready generally been widely described in the prior art and are subjectto permanent developments and improvement. Said transmissions thus musthave a sufficient number of forward gears, the same as one reverse gearand a ratio very well suited for motor vehicles with a high total spreadand favorable ratio ranges. They must also make possible a high startingratio in a forward direction and contain a direct gear, the same isadequate for use both in passenger and in commercial vehicles. Inaddition, said transmission must have low construction cost, especiallyrequire a low number of shifting elements and prevent double shifts in asequential shifting mode so that in case of shiftings in defined geargroups only one shifting element is changed.

The problem on which this invention is based is to propose a multiplestage transmission of the above mentioned type where the constructioncost is optimized and besides the efficiency degree in the main drivegears is improved with regard to towing and gearing losses. Furthermore,in the inventive multiple stage transmission, low torques act on theshifting elements and planetary gear sets and the rotational speeds ofthe shafts, shifting elements and planetary gear sets are kept low. Inaddition, the number of gears and the transmission spread are to beincreased so that advantageously seven or eight gears and at least onereverse gear, preferably two reverse gears, can be implemented. Theinventive transmission must also be adequate for any design of avehicle, particularly for a front-transverse arrangement.

SUMMARY OF THE INVENTION

The invention accordingly proposes a multiple stage transmission ofplanetary design which has one drive shaft and one driven shaft locatedin one housing. In addition, also provided are at least three planetarygear sets, at least six rotatable shafts, the same as at least sixshifting elements including brakes and clutches, the selectiveengagement of which by pairs produces different reduction ratios betweenthe drive shaft and the driven shaft so that preferably eight forwardgears and at least one reverse gear can be implemented.

The drive shaft is permanently connectable with the ring gear of thefirst planetary gear set and via one clutch with a fifth shaft which isconnected with the sun gear of the second planetary gear set andconnectable via one clutch with a sixth shaft, said sixth shaft beingconnected on one side with the spider of the first planetary gear setand, on the other side, loosely connectable via a clutch with a thirdshaft which is permanently connected with the spider of the secondplanetary gear set and the spider of the third planetary gear set andvia one brake attachable to the housing. Besides, the driven shaft isconnected with the ring gear of the third planetary gear set and thering gear of the second planetary gear set, one fourth shaft beingpermanently connected with the sun gear of the third planetary gear set,via one clutch loosely connectable with the drive shaft and via oneother brake attachable to the housing and sun gear of the firstplanetary gear set being non-rotatably connected with the housing.

By the inventive configuration of the multiple stage transmission,particularly for passenger motor vehicles, suitable ratios and aconsiderable increase in the total spread of the multiple stagetransmission results whereby an improvement in driving comfort and asignificant reduction in consumption are produced.

With the inventive multiple stage transmission, the construction cost isfurthermore considerably reduced due to a small number of shiftingelements, preferably two brakes and four clutches. It is advantageouslypossible with the inventive multiple stage transmission, to start offwith a hydrodynamic converter, an external starting clutch or with anyother suitable external starting element. It is also conceivable to havea starting off operation with one starting element integrated in thetransmission. Preferably suitable is a shifting element actuated in thefirst forward gear and in the first reverse gear.

With the inventive multiple stage transmission, a good degree ofefficiency in the main drive gears relative to towing and gearing lossesfurther results.

Besides, torque in the shifting elements and in the planetary gear setsof the multiple stage transmission is low whereby the wear isadvantageously reduced in the multiple stage transmission. The lowtorque also makes correspondingly small dimensions possible whereby theinstallation space needed and the attendant costs are reduced. Inaddition, the rotational speeds are also low for the shafts, theshifting elements and the planetary gear sets.

The inventive transmission is furthermore designed so that anadaptability to different drive line configurations is possible both inpower flow direction and with regard to space.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example, with referenceto the accompanying drawings in which:

FIG. 1 is a diagrammatic view of a preferred embodiment of an inventivemultiple stage transmission suitable for a front-transverseconstruction;

FIG. 2 is a configuration diagram by way of example of the inventivemultiple stage transmission according to FIG. 1;

FIG. 3 is a configuration diagram by way of example for the inventivemultiple stage transmission according to FIGS. 1 and 2;

FIG. 4 is a diagrammatic view of an embodiment of the inventive multiplegear transmission having a differential;

FIG. 5 is a diagrammatic view of an embodiment of the inventive multiplegear transmission with a clutch and a prime mover;

FIG. 6 is a diagrammatic view of an embodiment of the inventive multiplegear transmission having the transmission located between a startingelement and a prime mover;

FIG. 7 is a diagrammatic view of an embodiment of the inventive multiplegear transmission having a prime mover and a damper;

FIG. 8 is a diagrammatic view of an embodiment of the inventive multiplegear transmission with a cower take off for an additional unit; and

FIG. 9 is a diagrammatic view of an embodiment of the inventive multiplegear transmission with an electric machine.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, an inventive multiple stage transmission is shown having onedrive shaft 1 (An) and one driven shaft 2 (Ab) located in one housing G.

Three planetary gear sets P1, P2, P3 are provided. The first and secondplanetary gear sets P1 and P2 are preferably designed as minus planetarygear sets; the first planetary gear set serves as front-mounted rangechange set; the third planetary gear set is designed as a plus planetarygear set and, with the second planetary gear set P2, constitutes themain gear set.

As can be seen from FIG. 1, only six shifting elements are provided,namely, two brakes 03, 04, e.g., first brake 03 and second brake 04, andfour clutches 14, 15, 36, e.g., first clutch 14, second clutch 15, thirdclutch 36 and fourth clutch 56.

With said shifting elements, a selective shifting of eight forward gearsand preferably two reverse gears can be implemented. The inventivemultiple stage transmission has a total of six rotatable shafts, namely,the drive shaft, the driven shaft, a third shaft, a fourth shaft, afifth shaft and a sixth shaft 1, 2, 3, 4, 5, 6.

In the multiple stage transmission according to FIG. 1, it isinventively provided, that the input takes place by the shaft 1 which ispermanently connected with the ring gear of the first planetary gear setP1 and connectable, via one clutch 15, with the shaft 5 which isconnected with the sun gear of the second planetary gear set P2 andconnectable, via the clutch 56, with the shaft 6 which, on one side, isconnected with the spider of the first planetary gear set P1 and, on theother side, loosely connectable, via a clutch 36, with a shaft 3 whichis permanently connected with the spider of the second planetary gearset P2 and the spider of the third planetary gear set P3. Besides, theshaft 3 is attachable via one brake 03 to the housing G. The clutches 56and 36 are preferably disposed side by side. Within the scope of apreferred embodiment, they have a common external disc carrier situatedon the input side. The clutch 36 is preferably situated in power flowdirection behind the clutch 56.

In addition, the drive shaft 1 is loosely connectable via one clutch 14with the shaft 4 which is attachable to the housing G via one brake 04and connected with the sun gear of the third planetary gear set P3. Theclutches 14 and 15 are, likewise, preferably disposed side by side andcan have a common external disc carrier situated on the input side. Theclutch 14 is preferably situated in power flow direction behind theclutch 15.

The output inventively takes place via the shaft 2 which is connectedwith the ring gear of the third planetary gear set P3 and the ring gearof the second planetary gear set P2. Besides, the sun gear of the firstplanetary gear set is non-rotatably connected via one shaft 0 with thehousing G.

The spatial arrangement of the shifting elements can be arbitrary,limited only by the dimensions and the outer molding. As is to bedetermined from FIGS. 1 and 2, the clutches 56, 36, 14, 15, preferablyobserved radially, are situated approximately above the planetary gearsets; and other arrangements being also possible.

The embodiment, according to FIG. 2, differs from the embodimentaccording to FIG. 1 in that one freewheel FD is provided parallel withthe brake 04. Thereby high supporting torques can be reduced.

A variation (not shown) provides that the second planetary gear set P2with the third planetary gear set P3 is combined or reduced to form oneRavigneaux set with common spider and common ring gear. Compared withthe above described, this design has the advantage that less parts areneeded.

In FIG. 3 is shown, by way of example, a configuration diagram of theinventive multiple stage transmission according to FIGS. 1 and 2. Foreach gear, two shifting elements are engaged. From the configurationdiagram can be deduced the respective ratios i of the individual gearsteps and the ratio ranges to be determined therefrom. It can also bedetermined from the configuration diagram that in sequential shiftingmode, double shifts or group shifts are prevented since two adjacentgear steps use one shifting element in common. As can be seen from theconfiguration diagram, it is also possible to skip over gears withoutgroup shift. The eighth gear is preferably designed as a direct gear,the ratio ranges being small in the upper gears. The configurationdiagram is especially adequate for passenger cars. The transmission canalso be designed as a seven-gear transmission when the seventh gearfalls so that the ratio steps 1.27 and 1.1 are combined.

For the first three gears, the brake 04 is always closed. In addition,the clutch 56 for first gear, the clutch 15 for second gear and theclutch 36 for third gear are engaged. For the gears four, five and six,the clutch 36 is always engaged. Besides, the clutch 15 for fourth gear,the clutch 56 for fifth gear and clutch 14 for sixth gear are engaged.The seventh gear results by closing the clutches 14 and 56 and theeighth gear by engaging the clutches 14 and 15. The brake 03 and theclutch 15 for the first reverse gear and the brake 03 and the clutch 56for the second reverse gear are engaged.

According to the invention, it is possible to start-off with anintegrated shifting element (IAK). The clutch 56 is especially suitablesince, it is used in the first gear and in the reverse gear withoutreversal in direction of rotation. A reversal between the reverse gearsis possible without group shift which is advantageous for safetyvehicles, for example.

According to the invention, different gear ratios can result with thesame transmission diagram in conformity with shifting logic so that avariation in use specific to the vehicle is made possible.

It is further possible to provide on each adequate plane of the multiplestage transmission additional freewheels such as between one shaft andthe housing or in order optionally to connect two shafts.

On the input side or on the output side, as shown in FIG. 4, one of anaxle differential and/or a transfer differential 20 can be sitautedaccording to the invention.

Within the scope of an advantageous development, as shown in FIG. 5, thedrive shaft 1 can be separated, as needed, from a prime mover 26 by aclutch element CE, it being possible to use a hydrodynamic converter, ahydraulic clutch, a dry starting clutch, a wet starting clutch, amagnetic powder clutch, or a centrifugal clutch as a clutch element. Itis also possible, as shown in FIG. 6, to place such a starting element30 in a power flow direction downstream of the transmission in whichcase the drive shaft 1 is permanently connected with the crankshaft 28of the motor or the prime mover 26.

The inventive multiple stage transmission besides makes possible placinga torsional vibration damper 32 between the motor or the prime mover 26and the transmission, as shown in FIG. 7.

Within the scope of another embodiment of the invention it is possibleto situate a wear-free brake (only diagrammatically shown), such as ahydraulic or electric retarder or the like, upon each shaft, preferablyupon the drive shaft 1 or the driven shaft 2, which is especiallyimportant for use in commercial vehicles. It is also possible toprovide, as shown in FIG. 8, a power take-off 34 on at least one shaft,preferably on the drive shaft 1 or the driven shaft 2 for driving anadditional unit 38.

The used shifting elements can be designed as power shifting clutches orbrakes. Especially force-locking clutches or brakes like multi-discclutches, band brakes and/or tapered clutches can be used. Besides,form-locking brakes and/or clutches, such as synchronizers or dogclutches, can also be used as the shifting elements.

Another advantage of the multiple stage transmission introduced here isthat an electric machine 40 can be mounted upon at least one shaft as agenerator and/or as an additional prime mover, as shown in FIG. 9.

Every constructional design, especially every spatial arrangement of theplanetary gear sets and of the shifting elements per se the same asrelative to each other and insofar as technically convenient, obviouslyfalls under the scope of protection of the instant claims withoutaffecting the operation of the transmission such as indicated in theclaims even if said designs are not explicitly shown in the Figures orin the description.

Reference numerals 0 shaft 36 clutch 1 shaft 56 clutch 2 shaft P1planetary gear set 3 shaft P2 planetary gear set 4 shaft P3 planetarygear set 5 shaft An drive 6 shaft Ab drive 03 brake i ratio 04 brake Ghousing 14 clutch ED freewheel 15 clutch

1. A multiple stage transmission of a planetary design for an automatictransmission of a motor vehicle, the multiple stage transmissioncomprising: a housing (G) accommodating: a drive shaft (1) and a drivenshaft (2); a first planetary gear set (P1); a second planetary gear set(P2); a third planetary gear set (P3); at least third, fourth, fifth,and sixth rotatable shafts (3, 4, 5, 6) and a fixed shaft (0); at leastfirst, second, third, fourth, fifth and sixth shifting elements (03, 04,14, 15, 36, 56) including first and second brakes (03, 04) and first,second, third and fourth clutches (14, 15, 36, 56) which are selectivelyengageable to produce different gear ratios between the drive shaft (1)and the driven shaft (2) such that the transmission implements first,second, third, fourth, fifth, sixth and seventh forward gears and firstand second reverse gears; the drive shaft (1) being permanentlyconnectable with a ring gear of the first planetary gear set (P1) and,via the second clutch (15), with the fifth shaft (5) which is connectedwith a sun gear of the secondary planetary gear set (P2), and the fifthshaft (5) is connectable, via the fourth clutch (56), with the sixthshaft (6); the sixth shaft (6), adjacent a first side, being connectedwith a spider of the first planetary gear set (P1) and, adjacent asecond side thereof, being releasably connectable, via the third clutch(36), with the third shaft (3) which is permanently connected with aspider of the second planetary gear set (P2) and with a spider of thethird planetary gear set (P3), and the third shaft (3) beingconnectable, via the first brake (03), with the housing (G); the drivenshaft (2) being connected with a ring gear of the third planetary gearset (P3) and a ring gear of the second planetary gear set (P2); thefourth shaft (4) being permanently connected with a sun gear of thethird planetary gear set (P3), and the fourth shaft (4) being releasablyconnectable, via the first clutch (14), with the drive shaft (1) andbeing connectable, via the second brake (04), to the housing (G); andthe fixed shaft (0) fixedly connecting a sun gear of the first planetarygear set (P1) with the housing (G).
 2. The multiple stage transmissionaccording to claim 1, wherein the first, the second, the third, thefourth, the fifth, the sixth and the seventh forward gears are shiftablesuch that during shifting from one forward gear to one of a nextsequentially higher and a next sequentially lower forward gear, only onepreviously engaged shifting element is disengaged and only onepreviously unengaged shifting element is engaged.
 3. The multiple stagetransmission according to claim 1, wherein only two of the first, thesecond, the third, the fourth, the fifth and the sixth shifting elements(03, 04, 14, 15, 36, 56) are engaged for each one the first, the second,the third, the fourth, the fifth, the sixth and the seventh forwardgears and for at least one of the first and the second reverse gears. 4.The multiple stage transmission according to claim 1, wherein the secondbrake and the fourth clutch (04, 56) are engaged for the first forwardgear, the second brake and second clutch (04, 15) are engaged for thesecond forward gear, the second brake and the third clutch (04, 36) areengaged for the third forward gear, the second and the third clutches(15, 36) are engaged for the fourth forward gear, the third and thefourth clutches (36, 56) are engaged for the fifth forward gear, thefirst and the third clutches (14, 36) are engaged for the sixth forwardgear, and the first and the fourth clutches (14, 36) are engaged for theseventh forward gear.
 5. A multiple stage transmission of a planetarydesign for an automatic transmission of a motor vehicle, the multiplestage transmission comprising: a housing (G) accommodating: a driveshaft (1) and a driven shaft (2); a first planetary gear set (P1); asecond planetary gear set (P2); a third planetary gear set (P3); atleast third, fourth, fifth, and sixth rotatable shafts (3, 4, 5, 6) anda fixed shaft (0); at least first, second, third, fourth, fifth andsixth shifting elements (03, 04, 14, 15, 36, 56) including first andsecond brakes (03, 04) and first, second, third and fourth clutches(14,15, 36, 56) which are selectively engageable to produce differentgear ratios between the drive shaft (1) and the driven shaft (2) suchthat the transmission implements first, second, third, fourth, fifth,sixth, seventh and eighth forward gears and at least a first reversegear; the drive shaft (1) being permanently connectable with a ring gearof the first planetary gear set (P1) and, via the second clutch (15),with the fifth shaft (5) which is connected with a sun gear of thesecondary planetary gear set (P2), and the fifth shaft (5) isconnectable, via the fourth clutch (56), with the sixth shaft (6); thesixth shaft (6), adjacent a first side, being connected with a spider ofthe first planetary gear set (P1) and, adjacent a second side thereof,being releasably connectable, via the third clutch (36), with the thirdshaft (3) which is permanently connected with a spider of the secondplanetary gear set (P2) and with a spider of the third planetary gearset (P3), and the third shaft (3) being connectable, via the first brake(03), with the housing (G); the driven shaft (2) being connected with aring gear of the third planetary gear set (P3) and a ring gear of thesecond planetary gear set (P2); the fourth shaft (4) being permanentlyconnected with a sun gear of the third planetary gear set (P3), and thefourth shaft (4) being releasably connectable, via the first clutch(14), with the drive shaft (1) and being connectable, via the secondbrake (04), to the housing (G); and the fixed shaft (0) fixedlyconnecting a sun gear of the first planetary gear set (P1) with thehousing (G).
 6. The multiple stage transmission according to claim 1,wherein during a gear change from one of the first and the secondreverse gears to the other of the first and the second reverse gears,only one previously engaged shifting element is disengaged and onepreviously unengaged shifting element is engaged.
 7. The multiple stagetransmission according to claim 1, wherein the first brake (03) and thesecond clutch (15) are engaged for one of the first and the secondreverse gears and the first brake (03) and the fourth clutch (56) areengaged for the other of the first and the second reverse gears.
 8. Themultiple stage transmission according to claim 1, wherein at least oneof the first and the second clutches (14, 15) and the third and fourthclutches (36, 56) are respectively disposed side by side.
 9. Themultiple stage transmission according to claim 1, wherein at least oneof the first and the second clutches (14, 15) and the third and fourthclutches (36, 56) respectively have a common external disc carrier. 10.The multiple stage transmission according to claim 1, wherein at leastone of an external disc carrier of the first and the second clutches(14, 15) and an external disc carrier of the third and the fourthclutches (36, 56) is located on an drive input side of the multiplestage transmission.
 11. The multiple stage transmission according toclaim 1, wherein the first and the second planetary gear sets (P1, P2)are minus planetary gear sets and the third planetary gear set (P3) is aplus planetary gear set.
 12. The multiple stage transmission accordingto claim 1, wherein the second planetary gear set (P2) and the thirdplanetary gear set (P3) are combined as a Ravigneaux set with commonspider and common ring gear.
 13. The multiple stage transmissionaccording to claim 1, wherein the multiple stage transmission has atleast one freewheel located between the housing (G) and one of the driveshaft, the driven shaft, the third shaft, the fourth shaft, the fifthshaft, the sixth shaft (1, 2, 3, 4, 5, 6).
 14. A multiple stagetransmission of a planetary design for an automatic transmission of amotor vehicle, the multiple stage transmission comprising: a housing (G)accommodating: a drive shaft (1) and a driven shaft (2); a firstplanetary gear set (P1); a second planetary gear set (P2); a thirdplanetary gear set (P3); at least third, fourth, fifth, and sixthrotatable shafts (3, 4, 5, 6) and a fixed shaft (0); at least first,second, third, fourth, fifth and sixth shifting elements (03, 04, 14,15, 36, 56) including first and second brakes (03, 04) and first,second, third and fourth clutches (14, 15, 36, 56) which are selectivelyengageable to produce different gear ratios between the drive shaft (1)and the driven shaft (2) such that the transmission implements first,second, third, fourth, fifth, sixth, seventh and eighth forward gearsand first and second reverse gears; the drive shaft (1) beingpermanently connectable with a ring gear of the first planetary gear set(P1) and, via the second clutch (15), with the fifth shaft (5) which isconnected with a sun gear of the secondary planetary gear set (P2), andthe fifth shaft (5) is connectable, via the fourth clutch (56), with thesixth shaft (6); the sixth shaft (6), adjacent a first side, beingconnected with a spider of the first planetary gear set (P1) and,adjacent a second side thereof, being releasably connectable, via thethird clutch (36), with the third shaft (3) which is permanentlyconnected with a spider of the second planetary gear set (P2) and with aspider of the third planetary gear set (P3), and the third shaft (3)being connectable, via the first brake (03), with the housing (G); thedriven shaft (2) being connected with a ring gear of the third planetarygear set (P3) and a ring gear of the second planetary gear set (P2); thefourth shaft (4) being permanently connected with a sun gear of thethird planetary gear set (P3), and the fourth shaft (4) being releasablyconnectable, via the first clutch (14), with the drive shaft (1) andbeing connectable, via the second brake (04), to the housing (G); andthe fixed shaft (0) fixedly connecting a sun gear of the first planetarygear set (P1) with the housing (G).
 15. The multiple stage transmissionaccording to claim 1, wherein an input side and an output side of themultiple stage transmission are both located on a same side of thehousing (G).
 16. The multiple stage transmission according to claim 1,wherein one of an axle differential and a transfer differential isprovided upon an output side of the multiple stage transmission.
 17. Themultiple stage transmission according to claim 1, wherein a fifth clutchfacilitates disconnecting a prime mover of the multiple stagetransmission from the drive shaft (1) of the multiple stagetransmission.
 18. The multiple stage transmission according to claim 17,wherein at least one of the first, the second, the third and the fourthclutches is one of a hydrodynamic converter, a hydraulic clutch, a drystarting clutch, a wet starting clutch, a magnetic powder clutch and acentrifugal clutch.
 19. The multiple stage transmission according toclaim 17, wherein the drive shaft (1) is fixedly connected with acrankshaft of a prime mover and an external starting element is providedin a power flow direction downstream of the multiple stage transmission.20. The multiple stage transmission according to claim 1, wherein thedrive shaft (1) is fixedly connected with a crankshaft of a prime moverand a starting element of the multiple stage transmission facilitatesstarting of the multiple stage transmission.
 21. The multiple stagetransmission according to claim 20, wherein the fourth clutch (56) isused as a starting element for starting the multiple stage transmission.22. The multiple stage transmission according to claim 1, wherein atorsional vibration damper is located between a prime mover and themultiple stage transmission.
 23. The multiple stage transmissionaccording to claim 1, wherein a wear-free brake is provided on at leastone of the drive shaft (1), the driven shaft (2), the third, the fourth,the fifth and the sixth rotatable shafts of the multiple stagetransmission.
 24. The multiple stage transmission according to claim 1,wherein a power take-off is coupled to one of the drive shaft, thedriven shaft, the third shaft, the fourth shaft, the fifth shaft and thesixth shaft (1, 2, 3, 4, 5, 6) for driving an additional unit.
 25. Themultiple stage transmission according to claim 1, wherein a powertake-off is provided upon at least one of the drive shaft (1) and thedriven shaft (2).
 26. The multiple stage transmission according to claim25, wherein each of the first, the second, the third, the fourth, thefifth and the sixth shifting elements (03, 04, 14, 15, 36, 56) is one ofa power shifting clutch and a power shifting brake.
 27. The multiplestage transmission according to claim 1, wherein each of the first, thesecond, the third, the fourth, the fifth and the sixth shifting elements(03, 04, 14,15, 36, 56) is one of a multi-disc clutch, a band brake anda tapered clutch.
 28. The multiple stage transmission according to claim1, wherein each of the first, the second, the third, the fourth, thefifth and the sixth shifting elements (03, 04, 14,15, 36, 56) is one ofa form-locking brake and a form-locking clutch.
 29. The multiple stagetransmission according to claim 1, wherein an electric machine isconnected to at least one of the drive shaft, the driven shaft, thethird shaft, the fourth shaft, the fifth shaft and the sixth shaft (1,2, 3, 4, 5, 6) and functions as one of a generator and an additionalprime mover.
 30. The multiple stage transmission according to claim 1,wherein at least one of the first clutch, the second clutch, the thirdclutch and the fourth clutch (14, 15, 36, 56) are located substantiallyradially outward of the first, the second and the third planetary gearsets (P1, P2, P3).